ABSTRACT
Objectives: Primary care urgently needs treatments for COVID-19 patients because current options are limited, while these patients account for more than 90% of the people infected with SARS-CoV-2. Methods: We evaluated a throat spray containing three Lactobacillaceae strains with broad antiviral properties in a randomized double-blind placebo-controlled trial. Seventy-eight eligible COVID-19 patients were randomized to verum (n=41) and placebo (n=37) within 96 hours of positive PCR-based SARS-CoV-2 diagnosis and per-protocol analysis was performed. Symptoms and severity were reported daily via an online diary. Combined nose-throat swabs and dried blood spots were collected at regular time points in the study. Results: The daily reported symptoms were highly variable, with no added benefit for symptom resolution in the verum group. Specific monitoring of the applied lactobacilli strains showed that they were detectable via microbiome (27%) and qPCR analysis (82%) of the verum group. Their relative abundances were also negatively correlated with the acute symptom score. At the end of the trial, a trend towards lower SARS-CoV-2 viral loads was observed for the verum group (2/30, 6.7% positive) compared to the placebo group (7/27, 26% positive) (p = 0.07). Conclusions: Despite a trend towards lower SARS-CoV-2 viral loads at the end of the trial and a negative correlation between relative abundances of the applied lactobacilli in the microbiome and acute symptoms, we did not observe a significant effect on overall symptom score for the verum group. This suggests that studies with earlier application of the spray in larger study populations are needed to further assess application potential.
Subject(s)
COVID-19ABSTRACT
Respiratory viruses such as influenza viruses, respiratory syncytial virus (RSV), and coronaviruses initiate infection at the mucosal surfaces of the upper respiratory tract (URT), where the resident respiratory microbiome has an important gatekeeper function. In contrast to gut-targeting administration of beneficial bacteria against respiratory viral disease, topical URT administration of probiotics is currently underexplored, especially for the prevention and/or treatment of viral infections. Here, we report the selection and formulation of a broad-acting throat spray with live lactobacilli which induce interferon regulatory pathways and are able to inhibit respiratory viruses. Rational selection of Lactobacillaceae strains was based on safety, applicability, and potential antiviral and immunostimulatory efficacy in the URT. Three strains, Lacticaseibacillus casei AMBR2, Lacticaseibacillus rhamnosus GG and Lactiplantibacillus plantarum WCFS1 significantly reduced the cytopathogenic effects of RSV, influenza A/H1N1 and B viruses, and HCoV-229E coronavirus in co-culture models with bacteria, virus and host cells. Subsequently, these strains were formulated in a throat spray and human monocytes were employed to confirm the formulation process did not reduce the interferon regulatory pathway-inducing capacity. Administration of the throat spray in healthy volunteers revealed that the lactobacilli were capable of temporary colonization of the throat in a metabolically active form.
Subject(s)
Coronaviridae Infections , Influenza, Human , Respiratory Syncytial Virus Infections , Virus DiseasesABSTRACT
Background: SARS-CoV-2 human-to-animal transmission can lead to the establishment of novel reservoirs and the evolution of new variants with the potential to start new outbreaks in humans. Aim: We tested Norway rats inhabiting the sewer system of Antwerp, Belgium, for the presence of SARS-CoV-2 following a local COVID-19 epidemic peak. In addition, we discuss the use and interpretation of SARS-CoV-2 serological tests on non-human samples. Methods: Between November and December 2020, Norway rat oral swabs, feces and tissues from the sewer system of Antwerp were collected to be tested by RT-qPCR for the presence of SARS-CoV-2. Serum samples were screened for the presence of anti-SARS-CoV-2 IgG antibodies using a Luminex microsphere immunoassay (MIA). Samples considered positive were then checked for neutralizing antibodies using a conventional viral neutralization test (cVNT). Results: The serum of 35 rats was tested by MIA showing 3 potentially positive sera that were later shown to be negative by cVNT. All tissue samples of 39 rats analyzed tested negative for SARS-CoV-2 RNA. Conclusion: This is the first study that evaluates SARS-CoV-2 infection in urban rats. We can conclude that the sample of 39 rats had never been infected with SARS-CoV-2. We show that diagnostic serology tests can give misleading results when applied on non-human samples. SARS-CoV-2 monitoring activities should continue due to the emergence of new variants prone to infect Muridae rodents.
Subject(s)
COVID-19 , Rodent DiseasesABSTRACT
Wastewater-based epidemiology could be applied to track down SARS-CoV-2 outbreaks at high spatio-temporal resolution and could potentially be used as an early-warning for emergence of SARS-CoV-2 circulation in the general population. Epidemiological surveillance of SARS-CoV-2 could play a role in monitoring the spread of the virus in the population and controlling possible outbreaks. However, sensitive sample preparation and detection methods are necessary to detect trace levels of SARS-CoV-2 RNA in influent wastewater (IWW). Unlike predecessors, method development of a SARS-CoV-2 RNA concentration and detection procedure was performed with IWW samples with high viral SARS-CoV-2 loads (in combination with seeding IWW with a surrogate coronavirus). This is of importance since the SARS-CoV-2 genome in IWW might have already been subject to in-sewer degradation into smaller genome fragments or might be present in a different form (e.g. cell debris,...). Centricon Plus-70 (100 kDa) centrifugal filter devices resulted in the lowest and most reproducible Ct-values for SARS-CoV-2 RNA. Lowering pore sizes did not improve our limit of detection and quantification. Real-time polymerase chain reaction (qPCR) was employed for the amplification of the N1, N2, N3 and E_Sarbeco-gene. This is one of the first studies to apply digital polymerase chain reaction (dPCR) for the detection of SARS-CoV-2 RNA in IWW. Interestingly, qPCR results were comparable with dPCR results suggesting that qPCR is a valid method. In this study, dPCR was also used as a proxy to assess the precision of qPCR. In this light, dPCR showed high variability at low concentration levels (100 copies/{micro}L), indicating that variability in bioanalytical assays for SARS-CoV-2 RNA might be substantial. On average, the N2-gene showed high in-sample stability in IWW for 10 days of storage at 4 {degrees}C. Between-sample variability was substantial due to the low native concentrations in IWW. Additionally, the E-gene proved to be less stable compared to the N2-gene and showed higher variability. Freezing the IWW samples resulted in a 10-fold decay of loads of the N2- and E-gene in IWW. Although WBE can already aid in filling some knowledge gaps in the epidemiological surveillance of SARS-CoV-2, future WBE studies should aim to further validate and standardize bioanalytical assays, especially with regards to methodological limitations. HighlightsO_LIDevelopment of an analytical procedure for detection of SARS-CoV-2 RNA in wastewater C_LIO_LIExtraction recovery was evaluated in influent wastewater C_LIO_LIPrecision measured with dPCR used as a proxy for qPCR C_LIO_LIqPCR of the N2 gene fragment showed high in-sample stability of SARS-CoV-2 on average C_LI